Role of ruthenium content on studying excess conductivity and magneto-conductivity of SmBa2Cu3−xRuxO7−δ phase

Abstract

Superconducting samples of type SmBa2Cu3−xRuxO7−δ were prepared by a solid-state reaction technique. The electrical resistivity ρ(T) versus temperature for all prepared samples was measured in the absence and presence of magnetic field (0.44 T). The electrical resistivity data at zero magnetic field was analyzed using Aslamazov–Larkin (AL), Lawrence–Doniach (LD) and Maki–Thompson (MT) models in terms of fluctuation induced excess conductivity. Coherence length along c-axis $${\xi _c}\left( 0 \right)$$ , effective layer thickness of superconducting layers $$d$$ , the thermodynamic critical magnetic field $${B_c}(0)$$ , penetration depth $$\lambda (0)$$ , lower critical magnetic field $${B_{c1}}$$ , upper critical magnetic field $${B_{c2}}$$ , critical current density $${J_c}(0)$$ , Fermi velocity $${v_F}$$ , phase relaxation time of Cooper pair $${\tau _\varphi }$$ , coupling constant $$P$$ and energy required to break apart Cooper pair $${E_{{pb}}}$$ were calculated as a function of Ru-content. The magneto-conductivity data was analyzed using AL and MT models for layered superconductors. Coherence length along ab plane $${\xi _{ab}}(0)$$ and $${\xi _c}\left( 0 \right)$$ at 0 K, $${\tau _\varphi }$$ at 100 K and $${E_{{pb}}}$$ were also calculated as a function of Ru-content. The partial substitution of Cu2+ ions by Ru4+ ions up to 0.05 improved the superconducting properties of Sm-123 phase.